In Haunted Halls and the Doppleganger appears to be bugged. We've dropped him down to 0 health, but he won't die. He has the crested needed to unlock the door to the end fight. We've completed everything else that we can. Now we're just sitting around waiting for a DM to get off his extended coffee break to help us...
So, just wondering, has anyone else run into this? Maybe we're just doing something wrong???